Pump with piston and diaphragm



July 16. 1968 P. w. SCHLOSSER PUMP WITH PISTON AND DIAPHRAGM 2 Sheets-Sheet 1 Filed Oct. 28, 1966 P. w. SCHLOSSER 3,392,674

PUMP WITH PISTON AND DIAPHRAGM July 16, 1968 2 Sheets-Sheet 2 Filed Oct. 28, 1966 INVENTOR.

Paaf%./5%azrer gl ime United States Patent 3,392,674 PUMP WITH PISTON AND DIAPHRAGM Paul W. Schlosser, 4452 N. Avers Ave., Chicago, Ill. 60625 Filed Oct. 28, 1966, Ser. No. 590,429 18 Claims. (Cl. 103-44) ABSTRACT OF THE DISCLOSURE Pump having a pair of compartments sealingly separated by a flexible diaphragm. Hydraulic fluid pumped in and out of first compartment through inlet and outlet valves by piston reciprocating in cylinder sealed from the atmosphere. Seal on periphery of piston prevents fluid in first compartment from getting behind piston and permits fluid behind piston to be expelled into first compartment. Air bleed valve associated with first compartment. Diaphragm is actuated by hydraulic fluid to pump a second liquid in and out of second compartment through inlet and outlet valves. Effectiveness of seal formed by diaphragm increased in response to pressure stroke of piston. Air bleed valve associated with second compartment.

The present invention relates to a pump having a piston actuating a driving fluid actuating a flexible diaphragm pumping a driven fluid. The diaphragm is part of a separator assembly which seals 21 compartment containing the driving fluid from a compartment containing the driven fluid; and the separator assembly includes means for increasing the effectiveness of the seal in response to a pressure stroke by the piston when the latter actuates the driving fluid.

The piston reciprocates inwardly and outwardly within a cylinder; and the piston and cylinder each include sealing means cooperating to permit expulsion of fluid from behindthe piston to the front of the piston, during outward movement of the piston, and for impeding entry of fluid from the front of the piston to the rear thereof, during inward movement of the piston, while maintaining a pressure less than atmospheric within the cylinder to the rear of the piston.

The separator assembly also includes means which minimize wear on the diaphragm and extends the life thereof.

Other features and advantages are inherent in the structure claimed and disclosed or will become apparent to those skilled in the art from the following detailed description in conjunction with the accompanying diagrammatic drawings wherein:

FIGURE 1 is a side elevational view, partially in section, illustrating an embodiment of a pump constructed in accordance with the present invention;

FIGURE 2 is an enlarged exploded perspective view, partially cut away, of an embodiment of a separate assembly forming part of the pump of FIGURE 1;

FIGURE 3 is a plan view, partially in section and partially cut away, of the pump of FIGURE 1; and

FIGURE 4 is an enlarged fragmentary view, partially in section and partially cut away, of an embodiment of a piston assembly forming part of the pump of FIGURE 1. Referring to FIGURES 1 and 3, the embodiment of the pump illustrated therein includes first and second housing portions indicated generally at 11, 12, respectively, and secured together by bolts 22 (FIG. 3). Each housing portion 11, 12 has a first or inner open end in mutually facing disposition, and a second or outer open end opposite the first open end. Closing the outer open end of second housing portion 12 is an end member indicated generally at 13 and secured to housing portion 12 by bolts 23 (FIG. 3). Located at the outer open end of first housing portion 11 is a hollow cylinder indicated generally at 14 and at- 3,392,674 Patented July 16, 1968 tachcd to housing portion 11 by bolts 24 (FIG. 3). Disposed between housing portions 11 and 12, at the mutually facing inner open ends thereof, is a separator assembly indicated generally at 16. Separator assembly 16 is free floating in the sense that it is not secured by fasteners to either of the housing portions 11, 12, but is clamped therebetween. Located within cylinder 14 is a piston assembly indicated generally at 15.

First housing portion 11, separator assembly 16, cylinder 14 and piston assembly 15 define a driving fluid chamber 17. Second housing portion 12, separator assembly 16 and end member 13 define a driven fluid chamber 18.

In operation, piston assembly 15 reciprocates in inward and outward directions within cylinder 14 (to the left and to the right, respectively, as viewed in FIGURE 1). When piston assembly 15 moves inwardly, driving fluid within chamber 17 is urged against separator assembly 16 causing a flexible, fluid-impermeable diaphragm 19, constituting part of separator assembly 16, to flex tothe left, as viewed in FIGURE 1. When piston assembly 15 moves outwardly, the pressure within driving fluid chamber 17 is decreased, and flexible diaphragm 19 is urged to the right, as viewed in FIGURE 1.

When diaphragm 19 is urged to the right, pressure within driven fluid chamber 18 is decreased, an inlet valve 34, 35, 36 is opened, and driven fluid is drawn into chamber 18 through an inlet conduit 20. When diaphragm 19 is urged to the left, driven fluid within chamber 18 is expelled therefrom through an outlet channel 21 in housing portion 12. Separator assembly 16 prevents mixing of the respective fluids in compartments 17 and 18.

The components which define driven fluid chamber 18 will now be described in more detail.

End member 13 includes an outer portion 28 which bears against an O-ring seal 29 received within a circular indentation 30 located around the outer open end of housing portion 12. End member 13 also includes an inner portion 31 extending within housing portion 12 and including an inner recess 32 holding a valve seat 34 composed of a hard, Wear-resistant material, such as tungsten carbide, and constituting part of the inlet valve. The inlet valve also includes a ball 35 normally maintained in a seated position, closing inlet conduit 20, by a retainer indicated generally at 36.

Retainer 36 is constructed of a springy material and includes an inclined portion 37 and an upright portion 38 extending upwardly from inclined portion 37. Inclined portion 37 normally urges ball 35 in a downward direction to maintain the ball in a seated position against seat 34, thereby closing inlet conduit 20.

When diaphragm 19 is urged to the right, as viewed in FIGURE 1, the pressure within driven fluid chamber 18, to the right of ball 35, becomes less than the pressure within inlet conduit 20, to the left of ball 35; and this urges ball 35 to the right upwardly along inclined retainer portion 37 against the urging of gravity. The movement of ball 35 up inclined portion 37 is restrained by upright portion 38 of retainer 36. The distance between upright portion 38 and the inlet defined by valve seat 34 is less than the diameter of the ball.

If the magnitude of the forces urging ball 35 upwardly along inclined portion 37 is large enough, the ball will press against upright portion 38 and deflect portion 38 to the right, thus increasing the size of the opening through which driven fluid may enter compartment 18 and increas ing the amount of fluid which may enter on a given cycle of the pump. Being springy or elastic, upright portion 38 will return from its deflected to its upright position, illustrated in FIGURE 1, when the forces urging ball 35 thereagainst decrease sufliciently. The springiness of retainer 36 permits replacement of ball 35 without disassembling the retainer.

When flexible diaphragm 19 stops flexing to the right, ball 35 rolls downwardly along inclined retainer portion 37 to the closed position illustrated in FIGURE 1. When diaphragm 19 flexes to the left, driven fluid is expelled out of driven fluid compartment 18 through outlet channel 21 and opens an outlet valve assembly indicated generally at 41 in FIGURE 1.

Valve assembly 41 includes an upper portion 50 from which depends an externally threaded, cylindrical portion 42 threadedly engaged within a threaded opening 43 communicating with outlet channel 21 in housing portion 12. The innermost end of cylindrical portion 42 presses against a gasket 44 resting atop a shoulder 33 at the innermost end of threaded opening 43 in housing portion 12. Located atop gasket 44 is an annular valve seat 45 held in place by an interior shoulder 65 on valve housing portion 42. A ball 46 normally rests on seat 45.

When fluid is expelled from compartment 18, ball 46 is raised upwardly by the expelled fluid to permit the fluid to flow therearound and upwardly through the interior of housing portion 42. Upward movement of ball 46 is limited by a retainer 47 held in place by the lower end of a spring 48, the upper end of which engages an interior shoulder 49 in valve upper portion 50.

Gasket 44- is composed of conventional compressible gasket material and provides a seal to prevent leakage of driven fluid around the exterior of cylindrical portion 42. Gasket 44 also help deaden the sound of ball 46 striking against seat 45, when ball 46 returns to a position closing outlet conduit 21; and this occurs when diaphragm 19 stops flexing to the left.

Valve upper portion 50 has four internally threaded channels therein, each channel space 90 apart. In the illustrated embodiment, two of these channels are closed by externally threaded plugs 51, 52; and these channels normally perform no function, but are available for connection of externally threaded outlets such as 53, shown received in one of the other threaded channels in valve portion 50.

The fourth channel on valve portion 50 receives an air relief valve for driven fluid compartment 18. This valve is indicated generally at 55 in FIGURE 3 and includes a housing 56 having an elongated, hollow, cylindrical portion 57 terminating at an inner open end normally closed by a ball 58 attached to one end of a rod 59 having another end extending outwardly from housing 56 and terminating at a button 60 normally urged in an outward direction by one end of a spring 61, the other end of which seats against an annular member 62 located in a recess at the outermost portion of housing 56. Housing 56 also includes a port 63 communicating with a conduit 64 through which air is expelled in a manned now to be described.

Assuming there is air within driven fluid compartment 18, the air can be released while the pump is operating merely by depressing button 60. This pushes ball 58 inwardly, thus opening the innermost end of housing 56 to communication with compartment 18 and permitting air from compartment 18 to pass through hollow, cylindrical portion 57, through port 63 and through outlet conduit 64. Button 60 is held depressed until driven fluid is expeled through outlet 64, and this indicates that compartment 18 has been purged of air. Button 60 is then released and spring 61 returns button 60, rod 59 and ball 58 outwardly to their normal closed positions in which ball 58 blocks entry to fluid into valve housing 56. After ball 58 returns to its closed position, continuing operation of the pump builds up the fluid pressure, around the exterior of ball 58, urging the ball outwardly and preventing ball 58 from being moved inwardly from its normally closed position. This prevents button 60 from being depressed while the pump is in operation at a time 4 after air has been expelled from driven fluid compartment 18.

Gasket 44, previously described, is sufliciently compressible to permit threaded cylindrical portion 42 of valve assembly 41 to be turned through an angle suflicient to permit adjustment of driven outlet 53 or of air relief valve 55 to a particular angular orientation.

Referring again to FIGURE 1 and to the first and second housing portions 11, 12, respectively, at their mutually facing inner open ends, each housing portion 11, 12 has a recess or shoulder 26, 27, respectively, for clamping therebetween the outer peripheral portion 82 of the main body element 70 (FIG. 2) of separator assembly 16. Second housing portion 12 also includes another recess 25 located concentrically within outer shoulder 27. Recess 25 provides a clearance for flexing of diaphragm 19 during operation of the pump.

Referring to FIGURES 1 and 2, and describing separator assembly 16 in greater detail, main body element 70 also includes opposed first and second surfaces 66, 67 facing toward driving and driven fluid compartments 17, 18, respectively. Second surface 67 of element 70 includes a tapered portion 68 extending inwardly from peripheral portion 82 to a recess 69. Extending through main body element 70 are a plurality of fluid passages 71 arranged around a central opening 72 in which is slidably received a plug 73 having a threaded interior for engagement by a bolt 74 upon which are mounted a number of elements.

Mounted on bolt 74, adjacent first surface 66 of main body element 70, is a disk 76 sandwiched between an adjacent end of plug 73 and a nut 77. Mounted on bolt 74, next to the ned of plug 73 adjacent driven fluid compartment 18, and adjacent second surface 67 of main body element 70, is a relatively rigid metal washer and mounted next to metal washer 80 is flexible diaphragm 19. Mounted adjacent the surface of diaphragm 19 facing the interior of driven fluid compartment 18 is a relatively hard, rigid second metal washer 78 and sandwiched between the latter and diaphragm 19 is a relatively soft, pliable plastic washer 79. First metal washer 80, diaphragm 19, plastic washer 79 and second metal washer 78 are all held in place between a head 81 of bolt 74 and the adjacent end of plug 73.

The washers 78, 80 provide rigidity to the central portion of diaphragm 19, and are of a substantially smaller diameter than the diaphragm to permit flexibility of intermediate portions of the diaphragm. The outermost peripheral portion 182 of diaphragm 19 is clamped between shoulder 27 of second housing portion 12 and outer peripheral portion 82 of main body element 70.

First metal washer 80 has a diameter corresponding to the diameter of recess 69 in main body element 70 of separator assembly 16. In the illustrated embodiment, second metal washer 78 has a diameter slightly smaller than that of the first metal washer, and plastic washer 79 has a diameter slightly smaller than the second metal washer. In a typical embodiment, recess 69 and first metal washer 80 would have a diameter of about one and three-quarter inches, second metal washer 78 would have a diameter of about one and one-half inches, plastic washer 79 would have a diameter of about one and three-eighths inches and the flexible diaphragm 19 would have an unclamped diameter of about two and one-quarter inches.

Located on first surface 66 of main body element 70, facing toward driving fluid chamber 17, is a circular recess containing a first O-ring 83 positioned to be contacted by the outer peripheral portion of disk 76; and located concentrically outwardly of O-ring 83 is a second O-ring 84, also received within a circular recess in first surface 66 of main body element 70. Second O-ring 84 forms a seal between outer peripheral portion 82 of main body element 70 and shoulder 26 on first housing portion 11. This prevents leakage of driving fluid from driving fluid compartment 17 outwardly between main body element 70 and first housing portion 11.

In operation, when piston assembly moves inwardly (to the left, as viewed in FIGURE 1), driving fluid from driving fluid compartment 17 is forced through fluid passages 71 in main body element 70 into the space between diaphragm 19 and second surface 67 of main body element 70; and the driving fluid pushes against first metal washer 80 and the surface of diaphragm 19 facing main body element 70, thereby causing flexing of the diaphragm to the left, as viewed in FIGURE 1. As diaphragm 19 flexes to the left, all of the components of the separator assembly connected to the diaphragm for movement therewith (namely, metal washers 78, 80, plastic washer 79, plug 73, bolt 74 and disk 76) move to the left. Movement of these components to the left continues until the outer peripheral portion of disk 76 engages O-ring 83.

Engagement of disk 76 with O-ring 83 prevents further entry of driving fluid into fluid passages 71, thus stopping flexing movement of diaphragm 19 to the left. The spacing of disk 76, relative to diaphragm 19 and the other movable components of the separator assembly, is such that when disk 76 engages O-ring 83, diaphragm 19 is in a vertical planar position, with the diaphragm surface facing driven fluid compartment 18 corresponding to the dotted line 85 in FIGURE 1. Because it is not flexed beyond a vertical planar position, when flexed to the left, the wear on diaphragm 19 is much less than would be the case if it were flexed beyond such a position, and accordingly the life of the diaphragm is increased.

The effective area, on first surface 66 of main body element 70, against which driving fluid pressure is exerted, is an area having a diameter corresponding to the inner diameter of outer O-ring 84. This is greater than the effective area against which driving fluid pressure is exerted on second surface 67 of main body element 70, the latter area having a diameter defined by the outer diameter of tapered portion 68 on main body element 70.

Because the effective area on first surface 66 is greater than the effective area on second surface 67, there will be a greater fluid force exerted against surface 66 than against surface 67 of main body element 70 when the piston assembly 15 is moving inwardly. The net result is that main body element 90 will be urged toward driven fluid compartment 18 (to the left, as viewed in FIGURE 1), and clamped diaphragm peripheral portion 182 will be further compressed between the flat surface of shoulder 27 on second housing portion 12 and the opposed flat surface on outer peripheral portion 82 of main body element 70. This will cause clamped diaphragm portion 182 (composed of the material which will cold extrude) to cold extrude between clamping shoulder 27 and clamping peripheral portion 82, thus improving the seal therebetween to prevent the forced leakage of driving fluid therebetween during inward movement of piston assembly 15. Outward movement of the piston assembly decreases the clamping pressure on diaphragm portion 182, the clamping pressure being increased and decreased cyclically in response to inward and outward movement of the piston assembly. As shown in FIG- URE l, diaphragm portion 182 is clamped solely between opposed flat surfaces to form the seal between the driving fluid compartment and the driven fluid compartment.

When piston assembly 15 moves outwardly in cylinder 14 (to the right, as viewed in FIGURE 1), a substantial volume, communicating with driving fluid compartment 17, is displaced. This lowers the pressure within driving fluid compartment 17 and urges all the movable components of separator assembly 16 to the right. As a result, the seal between disk 76 and O-ring 83 is broken, and driving fluid passes from left to right through fluid passages 71 in main body element 70, with diaphragm 90 being flexed to the right. Movement of the movable components of separator assembly 16 to the right continues until first metal washer contacts the surface of recess 69, thereby closing fluid passages 71 in main body element 70 and preventing further passage of fluid therethrough from the left to the right.

The area of disk 76 is approximately the same as the area of the unclamped part of diaphragm 19 and is substantially larger than the area of piston assembly 15 which acts on the driving fluid, the latter area corresponding to that of the interior cross section of cylinder 14. As a result of these area relationships, it is easier to break the seal between disk 76 and O-ring 83 upon commencement of a suction stroke of piston assembly 15 (outward movement, to the right, as viewed in FIGURE 1) than would be the case if the disk were smaller in area.

First metal washer 80 serves as a back-stop divider between compartments 17 and 18 in case diaphragm 19 is punctured or wears out. In such a situation, washer 80 would engage recess 69 and prevent driven fluid in compartment 18 from flowing through fluid passages 71 into driving fluid chamber 17, during outward movement of piston assembly 15.

Relatively soft plastic washer 79 maintains hard, rigid second metal washer 78 spaced away from diaphragm 19 and out of contact with the diaphragm in all positions of flexing movement of the diaphragm. Soft washer 79 also prevents metal washer 78 from pressing abrasive particles against the adjoining surface of diaphragm 19. Plastic washer 79, being relatively soft, does not press abrasive particles into diaphragms 19 as would hard metal washer 78 if it were in contact with the diaphragm. Thus, plastic washer 79 prevents diaphragm 19 from being damaged and increases the life thereof.

Cylinder 14 and piston assembly 15 will now be described in detail. Referring to FIGURE 1, cylinder 14 has opposed inner and outer Open ends 172, 173 and includes a pehipheral portion which bears against an O-ring 91 mounted in a circular indentation at the outer open end of first housing portion 11. O-ring 91 is held between first housing portion 11 and. cylinder 14 and defines a seal to prevent the leakage of fluid from within driving fluid compartment 17 outwardly between first housing portion 11 and cylinder 14. The cylinder has an inner surface 181 which is hardened to resist wear and abrasion from components of the piston assembly.

Referring to FIGURES 1 and 4, piston assembly 15 typically is rigidly attached, by a bolt 101, to an inner end portion 102 of a connecting rod 94 having an outer end terminating at a bearing 95 mounted around an offset portion 96 of a crank shaft 97 powered by conventional motive means such as an electric motor (not shown).

Referring to FIGURE 4, piston assembly 15 comprises an internally threaded cylindrical member 100 threadedly engaged around bolt 101 and spaced from inner end portion 102 of connecting rod 94 by a backing washer 103 and a pair of spacing washers 104, 105, all loosely mounted on bolt 101. Secured to the inner face 170 of member 100, by the head 170 of bolt 101, is a retainer plate 108 having a larger diameter than member 100. Located around the outside of member 100, behind plate 108, is an annular, elastically deformable cup seal 106, composed of rubber, or the like, and having an outer circular flange 113, an inner circular flange 114 and a Web 115 between the two flanges. Also located around member 100 and disposed between cup seal 106 and backing washer 103 is an annular, elastically extrudable follower seal 107. Retainer plate 108 has a diameter larger than that of cup seal inner flange 114 and helps hold cup seal 106 in the desired position around member 100.

Closing the outer open end of cylinder 14 is a boot 110 composed of a flexible rubber or plastic material. Boot 110 is in the form of a tapered tubular member turned inside out, and has an inner edge portion 112 sealiugly fixed around inner end portion 102 of connecting rod 104 and an outer edge portion 111 sealingly fixed around cylinder 14 adjacent its outer open end 173. Boot 110 prevents air outside the pump from entering cylinder 14.

When the pump starts, during the first outward stroke of piston assembly 15 (to the right, as viewed in FIG- URE 4), part of the air in cylinder 14 between piston assembly 15 and boot 110 is expelled, around the outer flange 113 of U-cup seal 106, into driving fluid chamber 17. Then, when piston assembly 15 moves inwardly (to the left, as vie-wed in FIGURE 4) to complete its cycle, the pressure to the right of piston assembly 15, between the latter and boot 110, is lower than the pressure to the left of piston assembly 15, because of the expulsion of air from the right of the assembly to the left of the assembly during the previous outward stroke. Accordingly, outer flange 113 of cup seal 106 'will be urged, by the larger pressure to the left thereof, rearwardly and radially outwardly against the walls of cylinder 14, thus effecting a seal to prevent driving fluid in compartment 17 from passing around the piston assembly into the space between the latter and boot 110.

Boot 110 and cup seal 113 also cooperate to expel, back into driving fluid chamber 17, whatever fluid has leaked past the cup seal into the space behind piston assembly 15 between it and boot 110. More specifically, 'when piston assembly 15 again moves outwardly (to the right, as viewed in FIGURE 4), the decreasing pressure in driving fluid chamber 17 will be less than the increasing pressure in the space between piston assembly 15 and boot 110, thereby causing expulsion of driving fluid from said space back into driving fluid chamber 17. The fluid is expelled around the outer flange 113 of cup seal 106.

Annular follower seal 107 has an inner diameter greater than the outer diameter of member 100. As piston assembly 15 moves along its inward stroke (to the left, as viewed in FIGURE 4), the increasing pressure in driving fluid chamber 17 causes elastically deformable U-cup 106 to deform as follows: the inner part of web 115 and inner flange 114 are extruded into an annular space 174 between annular follower 107 and member 100; and outer flange 113 is forced radially outwardly and to the right so as to wipe against the wall of cylinder 14 and form a seal.

In addition to the deformation described above, elastic follower seal 107 is compressed between the relatively rigid web 115 of cup seal 106 (itself, forced rearwardly) and the rigid metal backing washer 103 located behind follower seal 107. Backing washing 103, being fixed behind follower seal 107, restricts rearward movement thereof. As the compressive pressure on the 'follo'wer seal increases, it extrudes radially inwardly into annular space 174 and radially outwardly against the wall of cylinder 14 to provide a further seal against leakage of driving fluid from compartment 17 around the outside of piston assembly 15.

Piston assembly 15 is illustrated in a some-what exaggerated rocked condition, in FIGURE 4. The piston assembly will rock as a result of the rigid connection thereof to the inner end portion 102 of connecting rod 94; but the sealing action described in the preceding paragraph occurs even though piston assembly 15 rocks during an inward stroke; and special structure to minimize rocking is not needed.

Boot 110 is essential to obtain the above-described sealing effect. Without a seal such as boot 110, air from outside the pump could enter cylinder 14 behind (to the right of) piston assembly 15 and prevent the formation of a partial vacuum in cylinder 14 behind the piston assembly. Without this partial vacuum, the cup seal flanges and the elastic follower seal would not be deformed in the manner described. With boot 110, the pressure behind the piston assembly is always less than atmospheric.

It is important that the piston assembly be constructed so as to provide an annular space 174 into which the cup seals inner flange 114 and the follower seal 107 can extrude. Without such an annular space to accommodate extrusion, the cup seals outer flange 113 would be extruded between the walls of cylinder 14 and the backing Washer 103 and would be worn away or damaged.

The pump also includes structure to permit driving fluid to be introduced into driving fluid chamber 17 and structure to permit driving fluid to be expelled from the driving fluid chamber.

Referring to FIGURES l and 3, there is illustrated a reservoir at for containing the driving fluid. Connected to reservoir 120 is a line 121 having an end 175 (FIG. 3) communicating with the hollow interior 176 of an externally threaded inlet valve having a body 122 threadedly engaged to pump housing portion 11. Interior 176 may be closed to the entry of driving fluid by a ball 123 when the latter is seated, as shown in FIGURE 3. On a suction stroke of piston assembly 15 (movement to the right, as viewed in FIGURE 1), ball 123 is urged to the left, as viewed in FIGURE 3, and unseated, thus opening the valves hollow interior 176 for the entry of liquid from line 121. Driving fluid passes from valve interior 176 to compartment 17 via an opening 124 (FIG. 1) extending through pump housing portion 11 and cylinder 14 and communicating with the inlet valve.

Ball 123 has a slightly smaller diameter than interior 176 to provide a slight clearance between ball 123 and the walls of interior 176 when the ball is unseated. The size of this clearance, being relatively small, permits the introduction of only a relatively small volume of driving fluid on a suction stroke of piston assembly 15, compared to the volume displaced by movement of the piston assembly to the right. The difference between the displaced volume and the volume of driving fluid entering through the inlet valve is made up by the movement of diaphragm 19. The smaller the volume of fluid entering through the inlet valve, the greater the movement of diaphragm 19. The greater the movement of diaphragm 19, the more driven fluid it draws into driven fluid compartment 18. The more driven fluid drawn into compartment 18 for a given stroke of piston assembly 15, the more efiicient the pump.

In situations wherein movement or further movement of the movable compartments of separator assembly 16 is not possible before termination of the inward stroke of piston assembly 15, driving fluid within compartment 17 is expelled outwardly from compartment 17 through structure now to be described.

Referring to FIGURES 1 and 3, driving fluid is expelled from driving fluid compartment 17 through a passage in pump housing portion 11. Passage 130 communicates with the hollow interior of a hollow bolt 131 which secures a valve assembly, indicated generally at 132, to pump housing portion 11. Valve assembly 132 includes a housing 129 which rests on a spacer 133 in turn resting on pump housing portion 11. Seal 134, between pump housing portion 11 and spacer 133, seal 135, between valve housing 129 and spacer 133, and seal 136, between valve housing 129 and the head 124 of bolt 131, are provided for the usual leakage-preventing purpose.

Referring to FIGURE 3, hollow bolt 131 includes a radially extending port 137 communicating with externally threaded tubular valve seat 138 threadedly engaged within valve housing 129. A ball 139 normally closes seat 138 and is surrounded by a tubular retainer 140' and held in place by one end of a retaining rod 141 extending longitudinally through a hollow interior portion of valve housing 129 and through an externally threaded hollow member 142 threadedly engaged within housing 129. Rod 141 is urged against ball 139 to hold the ball in a closed position on seat 138 by a spring 143.

When the pressure of fluid expelled from driving fluid compartment 17 exceeds the pressure of spring 143 against ball 139, the hall and rod 141 are pushed outwardly against the urging of spring 143, to provide an opening for the passage of driving fluid which now may pass upwardly through hollow bolt 131, through port 137 in bolt 131, through tubular valve seat 138 into the hollow interior portion 145 of housing 129. Communicating with hollow interior portion 145 is a port 146 in turn communicating with an externally threaded hollow fitting 147 threadedly engaged within port 146 and in turn communicating with one end 178 of a conduit 148 having another end 179 (FIG. 1) communicating with reservoir 120.

The pressure which spring 143 exerts against ball 139 may be adjusted by unscrewing an internally threaded cap 150 threadedly engaged to an outer end portion 180 of hollow member 142, and turning member 142, the pressure on spring 143 being increased or decreased depending upon the direction in which member 142 is turned.

A seal 151, between rod 141 and hollow member 142, and a seal 152, between cap 150 and hollow member 142, are provided for the usual leak-preventing purpose.

Structure is also provided to bleed air from driving fluid compartment 17, in situations wherein air may be present therein, such situations being, for example, when the pump is brand new or when it has been recently repaired.

Referring to FIGURE 3, hollow bolt 131 includes a second port 160 communicating with the hollow interior of an externally threaded fitting 161 threadedly engaged to housing 129 and having a valve seat 162 closed by a ball 163 held in place by one end of a bolt 164 having another end attached to a knob 165. Fitting 161 also includes a port 166 communicating with a transparent line 167.

When knob 165 is loosened sufliciently, ball 163 will be displaced'from its seat on an inward movement of piston assembly 15, and will return to its seat upon an outward movement of piston assembly 15. The net result is to eX- pel fluid through fitting 161 into line 167.

By observing transparent line 167, it can be determined whether driving fluid compartment 17 still contains air. As long as there are bubbles in the fluid being expelled through transparent line 167, there is air within compartment 17. When the fluid within transparent line 167 contains no observable bubbles, there is no longer any air within compartment 17; and knob 165 may be tightened to hold ball 163 in a closed position on seat 162; and the pump can be operated in the normal manner previously described.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as modifications will be obvious to those skilled in the art.

I claim:

1. In a pump:

means, including a first housing portion, defining a driving fluid compartment;

means, including a second housing portion, defining a driven fluid compartment;

hollow cylinder means communicating with said driving fluid compartment;

piston means mounted for reciprocal movement inwardly and outwardly within said cylinder means; separator means separating said compartments;

said separator means comprising means, including a flexible fluid-impermeable diaphragm, for sealing each of said fluid compartments from the other;

said diaphragm having an outer peripheral portion located between said first and second housing portions and clamped solely between opposed flat surfaces to form said seal;

said means defining each of the fluid compartments and said separator means including means cooperable for increasing and decreasing the clamping pressure of the opposed flat surfaces on the outer peripheral portion of said diaphragm cyclically in response to in ward and outward movement of the piston means to increase the effectiveness of said sealing means.

2. In a pump as recited in claim 1 wherein said flexible diaphragm is composed of material which will cold extrude.

3. In a pump: means, including a first housing portion, defining a driving fluid compartment; means, including a second housing portion, defining a driven fluid compartment; hollow cylinder means communicating with said driving fluid compartment; piston means mounted for reciprocal movement inwardly and outwardly within said cylinder means; separator means separating said compartments; said separator means comprising means, including a flexible fluid-impermeable diaphragm, for sealing each of said fluid compartments from the other; said separator means comprising a free-floating main body element having a first surface, facing toward said driving fluid compartment, and a second surface, opposite said first surface, facing toward said driven fluid compartment; said main body element including an outer peripheral portion; said flexible diaphragm being located between the main body element and said driven fluid. compartment; an outer peripheral portion on the flexible diaphragm; means on said second housing portion and on said outer peripheral portion of the main body element cooperating to clamp therebetween the outer peripheral portion of the flexible diahragm; said first and second housing portions and said separator means including means cooperable for cyclically increasing and decreasing the clamping pressure on the outer peripheral portion of the flexible diaphragm in response to inward and outward movement of the piston means, whereby an improved seal at the outer peripheral portion of the flexible diaphragm is effected. 4. In a pump as recited in claim 3 wherein: said flexible diaphragm is composed of material which will cold extrude; and said outer peripheral portion of the flexible diaphragm is clamped solely between opposed flat surfaces on the outer peripheral portion of the main body element and on the second housing portion to form said seal. 5. In a pump as recited in claim 4: said main body element having at least one fluid passage extending therethrough from the first to the second surface; said fluid passage comprising means for communicating with said driving fluid compartment; said flexible diaphragm and the second surface of the main body element defining a space communicating with the fluid passage in the main body element; the outer peripheral portion of said main body element being clamped between the first and second housing portions for movement relative to the outer peripheral portion of the flexible diaphragm in response to changes of driven fluid pressure; the first surface of the main body element having a greater area exposed to the pressure of the driving fluid than does said second surface of the main body element. 6. In a pump: hollow cylinder means having an inner open end and an outer open end; means communicating with said inner open end of the cylinder means and cooperating therewith to define a fluid enclosure; piston means mounted for reciprocal movement inwardly and outwardly within said cylinder means; said piston means having a front facing the inner open end of the cylinder means and a rear located behind said front;

sealing means on the piston means and on said cylinder means for permitting expulsion of fluid from behind said piston means to the front of the piston means during Outward movement of the piston means and for impeding entry of fluid from the front of the piston means to the rear thereof during inward movement of the piston means, while maintaing a pressure less than atmospheric within said cylinder means to the rear of the piston means.

7. In a pump is recited in claim 6:

a connecting rod extending through the open outer end of the hollow cylinder means and connected to said piston means;

said sealing means on the cylinder means comprising a flexible, fluid-impermeable tubular boot;

said tubular boot having one peripheral edge portion sealingly fixed around said connecting rod and another peripheral edge portion sealingly fixed around said cylinder means, whereby the outer open end of the cylinder means is sealed closed.

8. In a pump as recited in claim 6:

a connecting rod extending through the open outer end of the hollow cylinder means and connected to said piston means;

said piston means comprising a cylindrical member connected to said connecting rod;

said sealing means on the piston means comprising an annular, elastically deformable cup seal around said cylindrical member and an annular, disk-shaped follower seal located behind said cup seal;

said cup seal facing toward the front of the piston means and having an inner circular flange *on said cylindrical member, an outer circular flange for wiping the interior of said hollow cylinder means, and a web therebetween;

said annular follower seal having an inner diameter greater than the external diameter of the cylindrical member of the piston means, whereby said cylindrical member and said follower seal define an annular space therebetween;

a rigid backing member fixed behind said follower seal to restrict rearward movement of the latter; said follower seal being composed of elastically extrudable material;

whereby said annular follower seal is compressed between the web of the annular cup seal and the rigid backing member, during inward movement of the piston means, and elastically extrudes radially inwardly into said annular space and radially outwardly toward the interior of said hollow cylinder means.

9. In a pump as recited in claim 8:

said sealing means on the cylinder means comprising a flexible, fluid-impermeable tubular boot;

said tubular boot having one peripheral edge portion sealingly fixed around said connecting rod and another peripheral edge portion sealingly fixed around said cylinder means, whereby the outer open end of the cylinder means is sealed closed.

10. In a pump as recited in claim 8, wherein said connecting rod is rigidly attached to said piston means.

11. In a pump as recited in claim 6 and comprising:

air bleed valve means associated with said fluid enclosure;

and means for adjusting said air bleed valve means to an operable condition in which the valve means opens, in response to inward movement of the piston means, to bleed air from the fluid enclosure, and closes in response to outward movement of the piston means;

said adjusting means including means for adjusting the air bleed valve means to an inoperable condition in which the valve means is always closed.

12. In a pump as recited in claim 6 and comprising:

means defining a second fluid enclosure;

flexible diaphragm means sealing said first recited fluid enclosure from said second fluid enclosure;

air bleed valve means associated with said second fluid enclosure;

means mounting said air bleed valve means for movement between an open condition for bleeding air from the second fluid enclosure and a closed position;

means normally urging the air bleed valve to a closed position;

and means for preventing movement of the air bleed valve means to said open condition, after air has been bled from the second fluid enclosure, during expulsion of liquid from the second fluid enclosure.

13. In a pump having a driving fluid compartment and a driven fluid Compartment, separator means for separating said compartments, said separator means comprising:

a flexible, fluid-impermeable diaphragm;

a free-floating main body element having a first surface, facing toward said driving fluid compartment, and a second surface, opposite said first surface, facing toward said driven fluid compartment;

said main body element having at least one fluid passage extending therethrough from the first to the second surface;

a disk located adjacent the first surface of said main body element;

means connecting said disk to said diaphragm for movement of the disk with the diaphragm between a first disk position closing said fluid passage in the main body element and a nonclosing second disk position;

a rigid, relatively hard washer located adjacent one surface of said flexible diaphragm;

said hard washer facing the driven fluid comparatment;

a relatively soft washer located between said hard washer and said diaphragm;

means sandwiching together said hard washer, said soft washer and the diaphragm in coaxial relation;

the flexing part of said diaphragm overlapping the periphery of the hard washer, and the hard washer overlapping the periphery of the soft washer.

14. In a pump as recited in claim 13:

means mounting the flexible diaphragm for flexing movement toward and away from the driven fluid compartment;

said soft washer maintaining the hard washer out of contact with the diaphragm in all positions of flexing movement of the diaphragm.

15. In a pump:

means, including a first housing portion, defining a driving fluid compartment;

means, including a second housing portion, defining a driven fluid compartment;

hollow cylinder means communicating with said driving fluid compartment;

piston means mounted for reciprocal movement inwardly and outwardly within said cylinder means;

separator means separating said compartments;

said separator means comprising means, including a flexible fluid imperable diaphragm, for sealing each of said said fluid compartments from the other;

means mounting said flexible diaphragm for flexing movement in a first direction, toward the driven fluid compartment, in response to inward movement of the piston means and in a second direction, toward the driving fluid compartment, in response to outward movement of the piston means;

and means for limiting movement of the flexible diaphragm in one of said directions beyond a location at which the diaphragm is in a planar disposition.

16. In a pump:

means, including a first housing portion, defining a driving fluid compartment;

means, including a second housing portion, defining a driven fluid compartment;

hollow cylinder means communicating with said driving fluid compartment;

piston means mounted for reciprocal movement inwardly and outwardly within said cylinder means;

separator means separating said compartments;

said separator means comprising means, including a flexible fluid-impermeable diaphragm, for sealing each of said fluid compartments from the other;

means mounting said flexible diaphragm for flexing movement in a first direction, toward the driven fluid compartment, in response to inward movement of the piston means and in a second direction, toward the driving fluid compartment, in response to outward movement of the piston means;

a rigid, relatively hard washer located adjacent one surface of said flexible diaphragm;

a relatively soft washer located between said hard washer and said diaphragm;

means sandwiching together said hard washer, said soft washer and the diaphragm in coaxial relation;

the flexing part of said diaphragm overlapping the periphery of the hard washer, and the hard washer overlapping the periphery of the soft washer.

17. In a pump as recited in claim 16:

means for limiting movement of the flexible diaphragm in one of said directions beyond a location at which the diaphragm is in a planar disposition;

said soft washer maintaining the hard washer out of contact with the diaphragm in all positions of flexing movement of the diaphragm.

18. In a pump:

means, including a first housing portion, defining a driving fluid compartment;

means, including a second housing portion, defining a drivent fluid compartment;

hollow cylinder means communicating with said driving fluid compartment;

piston means mounted for reciprocal movement inwardly and outwardly within said cylinder means;

separator means separating said compartments;

said separator means comprising means, including a flexible fluid-impermeable diaphragm, for sealing each of said fluid compartments from the other;

a free-floating main 'body element having a first surface, facing toward said driving fluid compartment, and a second surface, opposite said first surface, facing toward said driven fluid compartment;

said main body element including an outer peripheral portion;

the outer peripheral portion of said main body element being clamped between the first and second housing portions;

said flexible diaphragm being located. between the main body element and said driven fluid compartment;

an outer peripheral portion on the flexible diaphragm;

means on said second housing portion and on said outer peripheral portion of the main body element cooperating to clamp therebetween the outer perpheral portion of the flexible diaphragm;

said main body element having at least one fluid passage extending therethrough from the first to the second surface;

said fluid passage comprising means for communicating with said driving fluid compartment;

said flexible diaphragm and the second surface of the main body element defining a space communicating with the fluid passage in the main body element;

a disk located adjacent the first surface of said main body element;

means connecting said disk to said diaphragm for movement of the disk with the diaphragm between a first disk position closing said fluid passage in the body element and a nonclosing second disk position;

said disk having an area substantially larger than the area of the interior cross section of said hollow cylinder means.

References Cited UNITED STATES PATENTS 581,469 4/1897 Mills 103153 2,303,597 12/1942 Adelson 103-44 2,792,790 5/1957 Capps 103-228 XR 3,052,188 9/1962 Wolf et a1. 103-44 3,207,081 9/1965 Bauer 103-153 3,318,250 5/1967 Bowen 103-44 45 ROBERT M. WALKER, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,392,674 July 16, 1968 Paul W. Schlosser It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 10, line 59, "driven" should read driving Signed and sealed this 16th day of December 1969.

(SEAL) Attest:

Edwa'rd M. Fletcher, Jr. WILLIAM E. SCHUYLER, JR. E

Attesting Officer 7 Commissioner of Patents 

